import math
x1, y1, x2, y2 = [float(_) for _ in input().split()]
print(math.sqrt(pow((x2-x1), 2)+pow((y2-y1), 2))) import math math float(_) for _ in input().split() for _ in input().split() _ input().split() ().split () input split for _ in input().split() float(_) float _ x1, y1, x2, y2 = [float(_) for _ in input().split()] x1 [float(_) for _ in input().split()] y1 x2 y2 print(math.sqrt(pow((x2-x1), 2)+pow((y2-y1), 2))) print math.sqrt(pow((x2-x1), 2)+pow((y2-y1), 2)) math.sqrt math sqrt pow((x2-x1), 2)+pow((y2-y1), 2) pow((x2-x1), 2) pow x2-x1 x2 x1 2 pow((y2-y1), 2) pow y2-y1 y2 y1 2 y2 = [float(_) for _ in input().split()] [float(_) for _ in input().split()] y2 x1, y1, x2, y2 = [float(_) for _ in input().split()] [float(_) for _ in input().split()] x1 x2, y2 = [float(_) for _ in input().split()] [float(_) for _ in input().split()] x2 y1, x2, y2 = [float(_) for _ in input().split()] [float(_) for _ in input().split()] y1
import math
x1, y1, x2, y2 = [float(_) for _ in input().split()]
print(math.sqrt(pow((x2-x1), 2)+pow((y2-y1), 2)))